Control of consecutively arranged inlet and exhaust valves in piston steam engines



June 26, 1934, A. SUNDER 1,964,226

CONTROL OF CONSECUTIVELY ARRANGED INLET AND EXHAUST VALVES IN- PISTON STEAM ENGINES Filed June 22. 1951 2 Sheets-Sheet 1 /nven/a/': Wa /w Jame 26, 1934. A.sUNDER 1,964,226

CONTROL OF CONSECUTIVELY ARRANGED INLET AND EXHAUST VALVES IN PISTON STEAM ENGINES Filed June 22. 1931 2 She ts-Sheet 2 lnvenlvp:

Patented June 26, 1934 UNITED STATES PATENT OFFICE CONTROL OF CONSECUTIVELY ARRANGED INLET AND EXHAUST VALVES IN PISTON STEAM ENGINES Application June 22, 1931, Serial No. 546,012

Germany June 27, 1930 4 Claims.

This invention relates to the control of double seated inlet and exhaust valves arranged on the ends of the cylinders and controlled by a common cam disc, in which the one valve is driven by the hollow spindle of the other valve. The

novelty consists primarily in that an inlet valve new arrangement the working stroke of the smaller valve takes place in the interior of the larger valve, the internal space of the larger valve forming therefore a portion of the overflow channel, the constructional lengths of the valve casing are small and the steam passages are very short in this casing.

Further, the cam disc actuating the valves is according to the invention so constructed that the control can be adjusted from the outside whilst the engine is running. Moreover the rocker levers are also adjustably mounted so that irregularities between the valve spindles and the cam disc can be corrected by adjustment, without the adjustment of the control being in any way afiected'.

An embodiment of the invention is illustrated by way of example in the accompanying drawings in which:'

Fig. 1 shows a section through a valve chest, containing the inlet and exhaust valves, as arranged on the end of a cylinder, the control device for the valves being shown in elevation.

Fig. 2 shows a similar valve chest with a slightly modified construction of the device efiecting the closing of the valves.

Fig. 3 shows in top plan view the arrangement of the intermediate levers between the valve spindles and the cam.

I Fig. 4 is a diagram, showing the adjustment of the'intermediate levers.

Fig. 5 is a diagram showing the adjustment ofthe rocker lever axles.

Fig; 6 shows in top plan view a suitable bearing of therocker lever.

Fig. 7 is a side elevation on lineVIL-VII of Fig. 6.

Fig. 8 is a side elevation on line VIII-VIII of Fig. 6, the rocker lever being combined at the same time with the compensating device illustrated in Figs. 3 and 4.

Fig. 9 shows the contr'ollingdevice of a compound steam engine in side elevation.

In the valve arrangement and valve control shown in Fig. 1 the inlet valve 1 and exhaust valve 2 on each end of a cylinder are arranged the one behind the other coaxially in a separate casing 3 placed on the cylinder in such a manner, that the partition 4 between two steam channels carries two valve seatingsurfaces arranged in one plane for the coaxial double seated valves arranged the one behind the other. In Fig. 2 these two valve seating surfaces are mutually displaced. In this arrangement of the valves only three steam channels 5, 6 and '7 are required for the steam flow in the casing 3 instead of four. The valve casing 3 and consequently alsothe cast cylinder block can be made lower than heretofore, as the inlet valve 1 when being lifted engages in the hollow space in the exhaust valve.

The control of the pairs of valves arranged on the two cylinder ends is effected by a single cam disc 0, loosely mounted on a pin 8 fixed on the cylinder. In order to enable the inlet and ex- 4 haust valves to be actuated by the cam disc, the inlet valve 1 is provided with a hollow spindle 9, shiftably mounted in the casing 3, the projecting end of said spindle extending to near the cam disc. 'In' a similar manner the exhaust valve 2 is also fitted with a hollow spindle 10 which is guided in the cover 11 of the casing 3, the projecting end of this spindle 10 carrying a spring cap 13controlled by a spring 12. The spring 12 0 holds the exhaust valve in its closed position.

In the coaxial hollow spindles 9, 10 push rods 14 and 15 are shiftably mounted, the contacting ends of which are cut off semi-circular along a certain length between the inlet and exhaust valves and sliding with their flat surfaces the one on the other. The end of one of the push rods, 14, has a collar bearing against the hollow spindle 10 of the exhaust valve 2, and the other push rod 15 has a. collar bearing against the hollow spindle 9 of. the inlet valve 1. A pressurespring 17 acts on the upper end of .the push rod a continuous or divided valve spindle 18 is arranged, which carries in its middle portion a collar 18', by which it is rigidly connected to the hub of the exhaust valve 2 by screwin keying or the like. In this instance the exhaust valve 2 is held in closed position by the spring 17. For eil'ecting the closing of the inlet valve the spring 12 is provided, the spring collar 13 of which presses downwards the hollow spindle 10 which is widened at its lower end and, provided with slots, engages over the arm cross of the exhaust valve 2 and bears against a flange of the hollow spindle 9 of the inlet valve 1.

The control of the inlet and exhaust valves is eiiected by a single cam disc 0 oscillatable on the pin 8 (Fig. 5).

The free ends of the rocker 20 and 22 engage one over the other in fork-shape in the axis of the valve spindles, the fork of the lever 20 acting directly on the valve spindle 9 of the inlet valve, whereas the end of the lever 22 is adapted to lift the push rod 14 or thevalve spindle 18 and therefore the exhaust valve 2. To enable the levers 22 to swing out, without influencing the valve spindles 9, these latter are provided with slots 23 in their end. Y

Rollers running on the segments 19 and 22 are mounted on the rocker levers 20 and 22.

The bearing of the rocker levers 20 and 22 is constructed so that their fulcrums are adjustable, these levers serving at the same time as compensating elements between the valve spindle ends and the cam disc. Fig. 4 shows more clearly the method of adjustment, which is characterized in that the levers rotate around the centre of the running on rollers 24 during their adjustment. Consequently, the adjustment has no effect whatever on the position of the running on rollers, so that the control once set and therefore the angle remains unaifected by the adjustment of the levers. For this purpose collars 27, having an arcuate part 26, are provided on the pivot pins 25 rigidly mounted on the cylinder, whereas the hubs 28 of the rocker lever engage with a corresponding counter groove in this arcuate part. The rocker lever can then be adjusted accordingly along this arcuate part. The adjusted position is secured by a nut mounted on an extension of lthe pin 25. The arcuate part is bent to a curve,

the centre of which coincides with the centre of the run on roller 24, Consequently, it is possible The adjustment of the control, whilst the.

engine is running, can be eifected by an arrangement as now described. The axle m of the carrying pins 25 of the rocker 1evers 20 and 22 is shifted around the centre n of the cam disc 0 along an are, having the radius R. within the limits m and m according to the necessary steam distribution figures, as illustrated diagrammatically in Fig. 5.

By the adjustment of the axle m the axle p of the roller 24 is also adjusted and consequently the angle a made smaller 1' or larger a" so that the roller 24 is moved towards or away from the high dwell of the cam 0, and consequently an earlier or later or closing 0! the valve isobtained. Asanbeseenfrom1=lg.9,theabutment points q of the ends of the levers 20 and 22 always remain in one plane, in spite of the shifting of the points m and 9. They shift only out of the central axis of the valve spindle towards s or t, but always within the valve spindle surface.

It may however also be arranged, as shown in Figs. 6 to 8, shiftable slide-like in an arcuate slot 44 of a bearing eye 45 by means of an arcuate part 25" and the like, arranged on a collar 25' and securely held in the actual position by set screws 46.

This arrangement may also be combined with the compensating mechanism illustrated in Figs. 3 and 4 and above described in that the extended pin 25 carries a sleeve 47, which also carries on a collar 27 the abovementioned arcuate part 26, in which the hub 28 of the intermediate lever is guided by means of a corresponding counter groove, and is adjustable and fixable in longitudinal direction thereto.

The drive of the control cam is effected by a rod system 49, engaging on the hub 30 at 48 by means of a pin, the control cams of difi'erent cylinders, in the case of multicylinder engines, being connected, as shown in Fig. 9, by a rocker lever system 50, 51.

1. A control for double seated inlet and exhaust valves, arranged one behind the other on the cylinder ends, comprising in combination with the inlet valve, the exhaust valve of larger diameter than said inlet valve, these two valves of each cylinder side being inserted between three steam channels in such a manner that mutually facing valve seats of both valves are situated on a partition between the channels and the open inlet valve projects into the space surrounded by the exhaust valve, a common cam in the midst of the cylinder to actuate all the valves, and intermediate levers adapted to trananit the movement of said cam -to said valves and an arrangement for adjusting said intermediate levers during work in order to compensate all irregularities in the control drive caused by unequal expansion under heat and erection.

2. A control as specified in claim 1, comprising in combination with the valves, hollow spindles carrying said valves, 8. dividcdpush rod in one of said' hollow spindles adapted to actuate one of said valves the contacting ends of said rod engaging one over the other by means of a sliding guide, a collar on said push rod bearing against said spindles, a closing means on the upper half of said push rod adapted to act on said inlet valve, and a closing means on the lower half of said hollow valve spindles acting on said exhaust valve.

3. A control as specified in claim 1, comprising in combination with the control cam and the intermediate levers, guides extending concentrically to the turning axis of said cam, and bearings for said levers adapted to be adjusted longitudinally of each guide whilst the engine is running.

4. A control as specified in claim. 1, comprising in combination with the levers and the cam disc, a roller on each of said levers adapted to run on said cam disc, a guide concentric to the centre of said roller, and a pivot pin 0! each of said levers adjustable in said guide.

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